The election has forced voters to confront the South American nation's dark recent past.

Some Peruvians mistrust Keiko Fujimori because her father Alberto is in jail for corruption and the slaughter of alleged terrorists in the 1990s. Others hope she will, like him, take a tough line on security to fight a wave of violent crime.

Both have vowed to heal divisions dating to the dark years of a 1980-2000 civil conflict involving leftists and the state.

"I want to be president of Peru to work for change... to build a great, prosperous country that is united and reconciled," Fujimori told supporters at her closing campaign rally late on Thursday.

Kuczynski, a flute-playing economist, stressed his long experience as a banker and former minister.

"We will not have to read the instruction manual, because we know what must be done," he told supporters.

Both candidates are right-leaning, US-educated politicians. Fujimori is the granddaughter of Japanese immigrants. Kuczynski is the son of a German doctor who treated lepers in the Amazon jungle.

Polls on Saturday showed Fujimori had lost her earlier lead as the two candidates were locked in a technical tie. Pollster GfK gave Kuczynski 51.1 percent to 48.9 percent for Fujimori.

The election campaigns have been stained by allegations of corruption and irregularities.

Ahead of the first round, opponents tried to get Keiko Fujimori excluded for alleged vote-buying, but the electoral board dismissed the case against her but expelled several other candidates.

A corruption scandal later struck the secretary-general of her party, Joaquin Ramirez. He resigned after media revealed the US Drug Enforcement Agency was investigating him over suspected money-laundering.

Both run-off candidates are seen as pro-market in their plans to further Peru's economic growth.

Peru's economy is outperforming most of its neighbour, but growth has declined during the term of outgoing President Ollanta Humala.

The International Monetary Fund forecasts it will grow by 3.7 percent this year.